West Pacific/2015/11W/Archive/5
Public advisory TROPICAL STORM NANGKA PUBLIC ADVISORY NUMBER 5 WIKI-HURRICANES FORECASTING CENTER 12:00 AM JST SUN JUL 05 2015 ...NANGKA TRAVERSING THROUGH THE MARSHALL ISLANDS... SUMMARY OF 12:00 AM JST...15:00 UTC...INFORMATION ------------------------------------------------------------------- LOCATION...11.1N, 167.4E CENTER POSITION CONFIDENCE: HIGH ... ± 25 MI... 40 KM ABOUT 690 MI...1,120 KM ENE OF PALIKIR, MICRONESIA MAXIMUM SUSTAINED WINDS...40 KT...45 MPH...75 KM/H MINIMUM BAROMETRIC PRESSURE...999 MB...29.50 INCHES PRESENT MOVEMENT...WNW AT 14 KT...16 MPH...26 KM/H DISCUSSION AND 48-HOUR OUTLOOK --------------------------------------------- At 12:00 am JST, the center of Tropical Storm Nangka was situated near 11.1N, 167.4E, or about 690 miles (1,120 kilometers) east-northeast of Palikir, Micronesia. Maximum sustained winds were 40 knots (45 mph, 65 km/h), with higher gusts. The minimum barometric pressure was 999 millibars (hPa; 29.50 inHg), and the cyclone was tracking west-northwest at 14 knots (16 mph, 26 km/h). Conditions are expected to be generally favorable for development in the short-term but may become slightly less conducive for intensification later on. NEXT ADVISORY ------------------- Next complete advisory at 06:00 am JST. $$ Forecaster TheAustinMan Discussion TROPICAL STORM NANGKA PUBLIC ADVISORY NUMBER 5 WIKI-HURRICANES FORECASTING CENTER 12:00 AM JST SUN JUL 05 2015 Nangka has become slightly better organized over the past six hours. Convection has managed to develop over the center, and microwave imagery rveals that there may be some attempts at an eyewall of some sort. Nangka has retained its curved band appearance and looks to be developing rainbands in its southwest quadrant. As the large rainband to the west of Nangka appears to be weakening at this time, it appears that the tropical storm may be attempting to consolidate into a smaller and more compact system. Despite these improvements, an ASCAT scatterometer pass only inidicated one wind barb of 40 knot winds, and although by its low-resolution nature often undersamples, typically a swath of 40 knot winds would be required to indicate higher winds. Thus, the current intensity for Nangka remains at 40 knots, though the pressure has been lowered due to the persistent firing of convection over the center; this is supported by current intensity estimates. The current heading for Nangka is 275/14, indicating generally west-northwestward motion. This is the result of the steering flow about the periphery of a 594 dm subtropical ridge over the Western Pacific that is expected to be the only major steering factor in the next five days. As a result, models are still in agreement that Nangka will continue to move towards the north-northwest, tracing an arc around part of the ridge; the WHFC forecast track is virtually an update of the previous track. This should bring Nangka near the Northern Mariana Islands in around 4-5 days. Nangka currently lies in favorable conditions for development with wind shear between 5-10 knots and warm oceanic waters. Given the latest trends, Nangka is expected to gradually intensify in these conditions, but intensification may stall in around 36-48 hours with shear expected to increase to near 30 knots, which may be problematic. After 48 hours, conditions are set to improve once again. This suggests a sort of staircase pattern of intensification for Nangka in the next five days, and the WHFC intensity forecast follows that philosophy, in addition to haivng projected intensities slightly biased towards the GFS/HWRF as they have been persistently showing a stronger system. INIT 04/1500Z 11.1N 167.4E 40 KT 45 MPH ... NEAR MARSHALL ISLANDS 12H 05/0000Z 10.8N, 168.0W 45 KT 50 MPH ... NEAR MARSHALL ISLANDS 24H 06/1200Z 11.1N 164.9E 55 KT 65 MPH 36H 07/0000Z 12.3N 158.7E 60 KT 70 MPH 48H 07/1200Z 13.5N 156.6E 60 KT 70 MPH 72H 08/0000Z 14.2N 156.2W 65 KT 75 MPH 96H 09/0000Z 17.8N 149.9E 75 KT 85 MPH ... NEAR NORTHERN MARIANA ISLANDS 120H 10/0000Z 20.3N 145.5E 95 KT 110 MPH ... NEAR NORTHERN MARIANA ISLANDS $$ Forecaster TheAustinMan